Question

Brain of cockroach is made of two groups of
A. One ganglia
B. Two ganglia
C. Three ganglia
D. Four ganglia

Answer 1

Hint:- Brain of cockroach is a part of CNS i.e. Central Nervous System located in the head region of the body. The nervous system of cockroaches is made up of a series of fixed ganglia which are arranged in segments. Ganglia is known as a cluster of neurons situated in the nervous system.

Complete step-by-step solution:-Cockroach comes under the phylum Arthropoda and class Insecta. They are usually omniverious. CNS (Central Nervous System) of cockroach consists of three supra-oesophageal ganglia circum-oesophageal and sub-esophageal ganglia. Supra-oesophagael ganglion is a bilobed mass formed by fusion of three pairs of ganglia. Those three pairs of ganglia are proto, deutero and tritocerebrum. Cerebrum is the main part of the brain or we can say it as cerebral ganglia. The brain part of cockroaches is made up of oesophageal ganglia. The part below the oesophagus is subesophageal ganglion also formed by three pairs of ganglia supra-oesophageal ganglia, supplies nerves to antennae and compound eyes (which are sense organs). Three main pairs of nerves rise from the supra-oesophageal ganglia are optics, antennary and labor frontal nerves. This comes under the peripheral nervous system. The only part which represents the brain is supra-oesophageal ganglia. And it is made up of three ganglia.
So the correct answer is, (C) three ganglia.

Note:- Brain of cockroach is made up of ganglia which are cell bodies of neurons and also the enlargement of nerve root. The function of the brain is to supply nerves to the sense organs. The nervous system in cockroaches is spread all over its body.